Bordetella pertussis organisms exert a complex influence on biological systems including those involved in immune responsiveness. Some of this complexity no doubt derives from the diverse biological activity of the component antigens of the organism (e.g., endotoxin, pertussigen, heat-labile toxin). This study will examine the interaction of pertussis antigens with immune cell mechanisms by defining the pertussis influence on macrophage phagocytosis, spreading, random migration, chemotaxis, lysosomal enzyme activity, accessory cell activity for in vitro antibody formation and blastogenesis, bactericidal activity, and non-specific protection to the lethal effects of virus challenge. The proposed project will study the macrophage as a specific target of pertussis influence and define the relationship between specific pertussis antigens and alteration of macrophage function. Pertussis organisms will be cultivated in specifically defined medium and phase I character and biological potency of the bacterium determined. Varying doses of killed organisms will be injected into mice and functional ability of explanted peritoneal and splenic macrophages determined. Also, the influence of pertussis in vitro on cultured macrophages will be determined. In addition, pertussis organisms and bacterial culture supernatants will be extracted for the isolation and purification of pertussis antigens. Purification of heat-labile toxin will be accomplished by ion exchange chromatography, endotoxin by differential centrifugation and pertussigen by gel filtration chromatography. The in vivo and in vitro influence of these pertussis antigens on macrophage function will be determined. These studies will add to the information concerning the cellular mechanisms involved in pertussis antigen immunomodulation especially in regard to influences on macrophage function.